Novel fiber coated with nanoporous carbons for headspace solid-phase microextraction of chlorophenols from aqueous media

Abstract

For the first time a novel fiber was prepared by coating CMK-5 onto the surface of a SPME (solid phase microextraction) support. The prepared material was characterized by X-ray diffraction (XRD), nitrogen adsorption–desorption and scanning electron microscopy (SEM) techniques. The efficiency of the fiber was evaluated using a gas chromatography-flame ionization detection (GC-FID) system for the extraction of four chlorophenolic compounds (2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol) from the headspace of aqueous samples. The results proved the ability of the proposed SPME fiber for determination of the selected chlorophenols (CPs). To optimize different parameters which influence the extraction efficiency, a Taguchi L₁₆(4⁴) orthogonal array experimental design was used. In order to increase the extraction of CPs onto the fiber and the elimination of tailing of peaks in the chromatogram, all the analytes were derivatized prior to extraction using acetic anhydride under alkaline conditions. The relative standard deviation (RSD%) was found to be in the range of 3.1–6.8% for a single fiber (n = 5) and 5.7–10.5% for fiber-to-fiber (n = 5). The limits of detection (LODs) ranged from 0.05 to 0.09 μg L⁻¹, which is lower than the European Community legislation limits for individual phenols in drinking water. Linearity was observed in the range of 2.5–800 μg L⁻¹ for 2-CP, 2,4-DCP, 2,4,6-TCP and 5–400 μg L⁻¹ for 4-CP. The relative recoveries of well, tap and sea water samples, spiked with constant levels of CPs, were 94.2–97.0%, 97.2–105.0% and 109.4–114.3%, respectively.